(query-replace-show-replacement): New defcustom.

(perform-replace): Use `match-substitute-replacement' if
`query-replace-show-replacement' is non-nil.

2 files changed, 25 insertions, 2 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 7dfea4936d7..ec6c084dd77 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,13 @@
+2007-11-10  Paul Pogonyshev  <pogonyshev@gmx.net>
+
+        * replace.el (query-replace-show-replacement): New defcustom.
+        (perform-replace): Use `match-substitute-replacement' if
+        `query-replace-show-replacement' is non-nil.
+
+2007-11-10  David Kastrup  <dak@gnu.org>
+
+        * subr.el (match-substitute-replacement): New function.
+
 2007-11-10  Carsten Dominik  <dominik@science.uva.nl>
 
         * files.el (auto-mode-alist): Select org-mode for files with the
diff --git a/lisp/replace.el b/lisp/replace.el
index 5fe8ad43d22..7876f9bb47c 100644
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -69,6 +69,12 @@ strings or patterns."
   :group 'matching
   :version "22.1")
 
+(defcustom query-replace-show-replacement t
+  "*Non-nil means to show what actual replacement text will be."
+  :type 'boolean
+  :group 'matching
+  :version "23.1")
+
 (defcustom query-replace-highlight t
   "*Non-nil means to highlight matches during query replacement."
   :type 'boolean
@@ -1570,10 +1576,17 @@ make, or the user didn't cancel the call."
                    (or delimited-flag regexp-flag) case-fold-search)
                   ;; Bind message-log-max so we don't fill up the message log
                   ;; with a bunch of identical messages.
-                  (let ((message-log-max nil))
+                  (let ((message-log-max nil)
+                        (replacement-presentation
+                         (if query-replace-show-replacement
+                             (save-match-data
+                               (set-match-data real-match-data)
+                               (match-substitute-replacement next-replacement
+                                                             nocasify literal))
+                           next-replacement)))
                     (message message
                              (query-replace-descr from-string)
-                             (query-replace-descr next-replacement)))
+                             (query-replace-descr replacement-presentation)))
                   (setq key (read-event))
                   ;; Necessary in case something happens during read-event
                   ;; that clobbers the match data.